Process of hardening copper alloys containing a small amount of tin.



UNITED STATES PATENT OFFICE.

HENRY BRYDA, OF BLACKSTONE, MASSACHUSETTS.

PROCESS OF HARDENING COPPER ALLOYS CONTAINING A SMALL AMOUNT OF TIN.

No Drawing.

To all whom it may concern Be it known that I, HENRY BRYDA, a citizen of the United States, residing at Blackstone, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Processes of Hardening Copper Alloys Containing a Small Amount of Tin; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to a method of treating copper alloys, and has special reference to the treatment. of alloys containing copper together with a small amount of tin, for hardening the same.

The process may be used in treating table knives or forks, and similar articles, in order to harden them suflicientlv for such uses.

The metal to be hardened, for example just after casting and as soon as the metal has solidified, is first treated by filing or otherwise grinding the surface, or a portion of the surface, to render the same smooth and shiny, and also to give the necessary cutting edge. The metal or alloy is then taken, and while it is still very hot, is placed upon a layer of loam, such a loam as may be obtained from a dry cellar, and which has never been exposed to either sun or rain, being found to be suitable. The loam preferably employed in this process contains an unusually large percentage of sand, which sand is very fine. The loam is also substantially free from organic matter, consequently the loam is very light colored. Practically any loam having these properties which has not been exposed either to sun or rain, can be used in carrying out the process, but that which has been obtained from considerable depth appears to give better results than that which has been obtained near the surface. The metal or alloy is placed upon a Specification of Letters Patent.

Patented May 5, 1914.

Application filed April 10, 1913. Serial No. 760,310.

layer of this. loam until the surface assumes a cloudy appearance, and when it is not desired to give the material its maximum hardness it is then removed from contact with said loam, and is placed on ashes, and is then allowed to remain until perfectly cold. The metal or alloy will be found to be somewhat harder than would be the case if the hotcasting had simply been allowed to cool in the mold, in the ordinary way.

If it is desired to further harden the alloy, the hot casting after filing or grinding is allowed to remain. in the loam, until a bluish color appears on the bright filed surface, and when this color appears the alloy is immediately removed from contact with the loam, and is allowed to cool in a suitable dry place.

What I claim is 1. A method of hardening a copper alloy containing a relatively small amount of tin, which comprises laying the alloy when hot upon a layer of dry loam which has not been allowed to come into contact with water or with sunshine, and allowing said alloy to remain on said loam, until the desired hardness is obtained, then removing it to a dry place, and allowing it to cool.

2. A method of hardening a copper alloy containing a small amount of tin, which con sists in filing a portion of the surface of said alloy while hot, then placing the alloy upon a layerof loam which has not been allowed. to come into contact with water, or sunshine, and allowing the same to remain until a bluish color is observed on the filed surface, then cooling the same in a dry place.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

- HENRY BRYDA. Witnesses:

JOHN B. SAWTELLE, FRANK W. MOCOOEY. 

